There have been numerous attempts to regulate grey water* discharge, but none (that I know of) have passed legislative approval.
There are no gray water laws in Ontario
, only because boat organizations banded together to "educate" the Ontario government
when these were proposed a few years ago.
* Gray water is defined as waste water from sinks and showers.
Direct discharges of gray water increases Biological Oxygen Demand (BOD) and nutrients in the water, lowers dissolved oxygen, and contributes to undesirable algal blooms.